Questions tagged [code-review]
This tag is intended for the review and improvement of style for already functioning code. It not meant to change the objective of the code.
451
questions
1
vote
0
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48
views
Why this code does not show three legend lines?
My code shows empty legend lines. What should I do to show the graph with three legend lines?
...
- 11
0
votes
1
answer
189
views
Fixing a code which covers $[-k,k]\times[-k,k]$ for a given $k\in\mathbb{N}$, with smaller rectangles of equal area?
Motivation: From this post we, initially, wanted to cover a rectangle using smaller, non-overlapping rectangles with the same area: the difference between the total area of the smaller rectangles and ...
- 29
3
votes
1
answer
165
views
Improve performance of Linear Optimization
EDIT
I am reframing the question here by pulling out the relevant part about linear optimization, you can find the original question and the entire code down below.
I am trying to increase the ...
- 376
4
votes
4
answers
385
views
A simpler or more concise way to divide the boundary of a polygon into equal arc lengths?
I am really looking just for the least amount of code needed to do this but it is still readable.
Here is the same polygon but the border is respectively split up into 10, 20, and 30 points along the ...
- 445
1
vote
0
answers
162
views
How to show the limit of two functions in a code approach zero?
I don't know how to shorten the program, the entire code is required to understand everything:
...
- 29
1
vote
1
answer
61
views
How to join two disconnected curves with listplot
Actually I want to join the blue and the red curve with another curve (definitely not a straight line, but some smooth curve) to show the transition from blue to red. How can I do this? Please help. ...
- 43
2
votes
0
answers
51
views
Plotting diagram of complex equation [closed]
I have this equation:
q1[t_] := -I*γ*Sin[θ] + ((γ*Cos[θ])/n^2)*(I*ξ[t]*y+z*α[t])
and the main code is the following with the definition of each parameters:
...
- 63
3
votes
1
answer
80
views
Why is StoppingTest in red? What other option to stop NDSolve?
The following stripped down code works, but I'm experiencing some strange warnings: from an old document made with Mathematica 7.0 (but used in version 13.2), I'm getting several warning messages ...
- 3,949
4
votes
3
answers
155
views
how to balance a matrix by proportional adjustment of rows and columns
Given a matrix:
ClearAll[mat, refR, refC];
mat = {
{21.2, 29, 19.9},
{9, 48.8, 22.4},
{49.8, 62.2, 7.8}
};
I want to adjust the elements of ...
- 5,303
0
votes
0
answers
51
views
Part specification error
I am doing a solved exercise shared here.
However, while running the code, I encountered an error on page-8, under the Dynamics section.
with error :
I think this error is due to the absence of ...
- 1,502
1
vote
2
answers
119
views
Number operator
Suppose CR is my creation operator and AR is my annihilation operator.
I have to show that ...
- 1,502
0
votes
0
answers
64
views
Mathematical Equations Puzzle: Perfect Sixes
pI have given the following problem to my students
Write some code that solves the perfect sixes problem for all numbers it works for!
The perfect sixes problem asks you to solve some equations:
\...
1
vote
1
answer
95
views
How can I roll up a line to get a circle? [closed]
I am trying to transfer n1=4 points that I have on a line, on a circle. suppose:
...
1
vote
0
answers
96
views
Matlab to Mathematica code to solve system of ODEs [closed]
I have the following system of second order non-homogeneous DEs:
\begin{align}
0 &= 2 x_t - J_{\pi_t}(x_t) \frac{\epsilon - 1}{\theta} (1 + \varphi) + \frac{\partial J_{x_t}(x_t)}{\partial x_t} \...
- 407
0
votes
0
answers
32
views
Discretizing Geographics
I am in need of boundary regions for cities. A previous question shows that it is possible to discretize CountryData:
...
- 19.6k
0
votes
0
answers
52
views
How to solve Equation for different variable in Mathematica?
I want to solve the given equation for $(n=m=3)$ and I want the output variable $q_{1,1}, q_{1,2}, q_{2,1}, q_{2,2}$
Given Equation
Given Equation-2
The output should be
required Output
Here is my ...
- 1
2
votes
1
answer
89
views
Create a set of vectors from given pairwise dot product
Assume I am given a list of all the pairwise dot products of an unknown set of $n$ vectors. How can I efficiently generate such a set (or all possible sets) with the extra constraint that all vectors ...
- 539
1
vote
2
answers
101
views
How to improve this plot? Behaviour of the derivative
I wanted to plot the function
$$f(x) = \frac{x^2}{2} - 3\ln(\vert x\vert +2)$$
together with its derivative
$$f'(x) = x - \frac{3x}{\vert x \vert(\vert x\vert +2)}$$
which exhibites a cusp point at $x ...
- 767
2
votes
0
answers
103
views
Placing shapes along a square spiral
Proposed code example is inspired by the main idea of this challenge.
Wolfram Language provides great opportunities in computational geometry.
But not all of them are equal in terms of speed and ...
- 1,085
1
vote
2
answers
72
views
Defining and executing large matrix operators on vectors efficiently
For an $N$-qubit system, I am interested in coding, in an efficient way, the following set of Kraus operators $\{A_c\}_c$ defined in the computational basis as
\begin{align}
\hat{A}_c := \sum_{m=...
- 295
1
vote
1
answer
50
views
Roots of polynomial using sigmma notation (code improvement) and some maths related question
Comes from exploring roots of polynomials and using the recurrence relationship of $S_n = \sum \alpha^n$ notation. Like this:
$$
S_2 = \left( \sum \alpha \right)^2 - 2 \sum \alpha \beta
$$
where $\...
- 1,460
9
votes
1
answer
591
views
Mathematica for Theoretical Physics by Gerd Baumann : Henonmap
I was following a solved problem from the book mentioned below on the Henon map. However, even after correcting that I still get an error on execution. I am unable to find the exact cause.
...
- 1,502
1
vote
1
answer
142
views
Again with filling in a plot
I really don't understand how filling works, and here I am with a new question about.
I need to colour the region in the first quadrant, created by the functions $x+2$ and $-3x+5$. Hence $x$ runs from ...
- 767
4
votes
1
answer
186
views
Collapse (hide) code inside a function
I often use structures similar to the "func" below, however I would like to be able to "hide" the function definitions (similar to cell grouping using a group opener). I think an ...
- 151
4
votes
1
answer
94
views
Speed up functions using variable types but not Compile
I am writing a large numerical code and I have set up many functions that take several arguments as input. In the functions I am using several built in Mathematica functions, such as Sum[], Part[], ...
- 243
2
votes
1
answer
112
views
Unable to solve the given equation
I am trying to solve the given system in terms of $r$, for which I use the following code:
...
- 899
1
vote
1
answer
163
views
Plot of massless particles on unstable null circular geodesic : Finding an alternative for Graphics`Mesh`FindIntersections and reducing code length
My friend and I were trying to reproduce Figure 4(left) from this paper(page 7). We succeeded in reproducing the result after writing a lengthy and complicated code. Here I dissect the code in steps:
...
- 899
0
votes
1
answer
77
views
Trouble with output of Reduce as a root object for a 3d Plot
I am trying to find the value of $r_0$ using $L^2=\frac{{r_0}^3 f'({r_0})}{2 f({r_0})-{r_0} f'({r_0})}$ and making a 3d plot with the help of the code given below:
...
- 899
4
votes
5
answers
186
views
Converting specific positions of a List into Sublist
Suppose I have a List of numbers:
num = Range[5]
I want to combine the second and the third element into a sublist to get the result as {1,{2,3},4,5}.
I tried ...
- 899
1
vote
1
answer
73
views
Implementing a way of generating binary data for use in a logistic regression
Background
I want to generate a set of test data to be used in a logisitic regression.
As an example consider the scenario where a cannonball is fired at a wall. There are only two outcomes: the wall ...
- 107
1
vote
1
answer
128
views
How to increase efficiency of Mathematica code?
I have a code that runs as it is supposed to, but it takes around 8 hours to reach the solution with the step size necessary to find agreement between the analytical and computational solutions. As I ...
- 31
1
vote
2
answers
126
views
How can I improve this code?
The code below is working well, but it's very slow in the Manipulate box. I know that the Do and AppendTo parts aren't very ...
- 3,949
1
vote
1
answer
79
views
How to use an "otherwise" clause in `Which`
I want to classify a set of vectors according to the number and position of zeroes they contain. The components of the vectors are non-negative. I'm using
...
- 563
0
votes
0
answers
71
views
How do we define the function near the end of my post?
Suppose I have two sets $F_{1,n}$ and $F_{2,n}$ written as:
...
- 29
6
votes
4
answers
412
views
Is there a more elegant solution than f[a, b, Sequence@@#3,...]?
I am trying to construct a list of many possible combinations using Outer and Permutations. Something that looks like that:
<...
- 525
1
vote
0
answers
70
views
How to rescale list to interval $(0,1)$ [closed]
Imagine I have an arbitrary list
l = RandomReal[{-5, 10}, 10]
Out[]= {4.17452, 1.75762, 4.16905, -3.63225, 8.34172, 5.39626, -4.2107, 3.50873, -1.52441, -3.7147}
...
- 4,187
0
votes
1
answer
91
views
3
votes
2
answers
105
views
Check certain expression using a while loop to run through all posibilities in a range
Well, I have written the following code (using the fast square root test found in this answer):
...
- 1,941
1
vote
1
answer
48
views
How to number each element of a list to form a table of points? [closed]
Suppose we have a list given below
OurList={a,b,c,d,e}
Is there a way to attribute a number to each element of OurList so that we could form a table of points? The ...
- 53
0
votes
0
answers
20
views
Table of time-varing calculation slower to the point of kernel blowing up
There is a complicated function obtained by numerically solving a pde, let us call it $u(t,x,z)$.
For this $u$, I want to calculate the global maximum of $u^2$ at a fixed position of $z$, and plot ...
- 53
5
votes
1
answer
130
views
1
vote
1
answer
103
views
1
vote
0
answers
99
views
How to fix Mathematica crashing in the following case?
I have a problem with Mathematica when trying to glue two tables together.
The tables have the form
...
- 4,984
5
votes
1
answer
225
views
Speeding up Fourier transform and eigenvector calculation
I have a matrix $M$ in Bloch basis (momentum space). Then I have to take Fourier transform of $M$ to go to real space. The size of this lattice in real space can be fixed to some value $N_{unit}$.
...
- 583
3
votes
1
answer
231
views
Unbounded solution at boundaries with few combination of values in this BVP solution
I had asked a question here regarding solution to a BVP problem. bbgodfrey provided an excellent answer using the method of integrated least squares.
However, for a few specific set of values of ...
- 297
1
vote
0
answers
86
views
Code review of my animation of Ellipsoid method
Feel free to suggest improvements (code-review) to my two functions (calculation and animation).
They were made to visualize the workings of the Ellipsoid method in two dimensions.
For example, see ...
- 622
1
vote
1
answer
248
views
How to fourier transform a numerical solution?
I numerically solved a wave equation and want to fourier transform the solution uwave1(t,x,z) at a particular instant of time t and position z. The code is as follows:
...
- 53
1
vote
0
answers
89
views
Shortest paths Knights Tour
I am trying to print the minimum steps needed to traverse a chessboard as a knight from one diagonal position to the other. I have the following code:
Building the chessboard
I started with creating ...
0
votes
1
answer
42
views
Updating the association with answers from the TrigProperties Function
I have created a list of rules I would like to update with values. My goal here is to be able to write the following:
...
0
votes
1
answer
60
views
Check if a fraction leads to an integer, choose $r$ and run trough $0\le a\le n$ and go to $r+1$
Well, I am trying to do the following: I have two functions $y(r,a)$ and $z(r,a)$ and I want to check of the division of both those functions leads to an integer. In order to do that I want to choose ...
- 1,941